This invention relates to the disposal of arsenic-containing wastes. More specifically, it relates to a method for treating arsenic-containing waste materials so that they are rendered suitable for sanitary landfills.
Waste materials containing high concentrations of arsenic and/or arsenic compounds are obtained in certain commercial processes. One such is in the smelting of nickel-containing ores to obtain nickel metal. These ores often contain arsenic oxides as well as nickel constituents so that a byproduct containing arsenic is produced along with the nickel metal. Similarly, shale oil produced from any oil shales contains high concentrations of arsenic. These shale oils are virtually unsaleable until the arsenic is removed, such as by the process described in my U.S. Pat. No. 4,046,674 or by methods as shown, for example, in U.S. Pat. Nos. 3,804,750 and 3,933,624. In all such processes, however, a problem is ultimately encountered in disposing of the arsenic-containing byproduct.
At the present time arsenic wastes are usually stored, much like radioactive wastes, in holding areas designed to prevent the release of the arsenic into the ground. Some of the arsenic is marketable, primarily to steel producers, but the proportion thus sold is relatively small. Hence, the amount of arsenic held in holding areas is continually increasing, primarily because no satisfactory means are available for rendering it innocuous for use as a landfill.